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Abstract:
The synthesis and spectroscopic investigation of aza-crown ethers with anthraquinone- and 1-aminoanthraquinone-functionalized side chains are described. Cation-induced shifts in the UV/VIS absorption spectra of the ligands dissolved in propylene carbonate are observed only for Li+ among the alkali metal ions and for Mg2+ among the alkaline earth metal ions as well as for Ag+ and Tl+. Only hypsochromic shifts of the absorption spectra of anthraquinone-bearing aza-crown ethers are observed on protonation. The variations of the extinction coefficients are discussed with respect to the sequence of protonation of the different amino groups.
